Find a common denominator (the product or the LCM of the denominators), convert the fractions and add the numerators. Example: 1/2 + 1/3 = 3/6 + 2/6 = 5/6. The tool does this automatically.
Carregando ferramenta… / Loading tool…
Add, subtract, multiply and divide fractions with a simplified result.
Adding 1/3 to 0.333… on a computer gives a weird number, because fractions and floating-point decimals do not get along. This calculator fixes that by working with exact integer arithmetic: it treats each fraction as a pair of integers and never converts to a decimal during the computation, which eliminates rounding errors. To add or subtract it finds a common denominator; to multiply it multiplies numerators and denominators; to divide it multiplies by the reciprocal. The result is reduced by the greatest common divisor (GCD) and also shown as a mixed number and a decimal, flagged with ≈ when the decimal is repeating (non-terminating). The step-by-step keeps the math transparent, great for checking or studying.
Adding and subtracting require equal denominators: the tool finds a common denominator (by the product or the LCM), converts both fractions and operates on the numerators. Multiplying is the most direct: multiply numerator by numerator and denominator by denominator, "straight across."
Dividing has a trick: dividing by a fraction is the same as multiplying by its reciprocal (swap the second fraction's numerator and denominator). After any operation, the result is reduced to lowest terms by dividing both terms by the GCD, which is why the answer comes out simplified.
Example 1, addition: 3/4 + 5/6. The common denominator is 12, so 3/4 = 9/12 and 5/6 = 10/12; adding gives 19/12. Since 19 is larger than 12, the mixed number is 1 7/12, and the decimal ≈ 1.5833… (repeating, marked with ≈).
Example 2, multiplication: 2/3 × 3/4 = (2×3)/(3×4) = 6/12, which simplifies to 1/2 (exact decimal 0.5). The tool shows both steps, the raw product and the reduced form, so you can follow the simplification.
The same value appears in three forms because each is useful in a different context. The reduced fraction (lowest terms) is the canonical mathematical answer. The mixed number (whole part + proper fraction, like 1 7/12) is more intuitive for everyday measures, recipes, woodworking, distances.
The decimal makes it easy to compare or carry the value into an ordinary calculator, but not every fraction becomes an exact decimal: 1/3, for example, is 0.333… forever. The tool flags those cases with ≈, making clear the decimal is an approximation while the fraction is the exact value.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
<iframe
src="https://jkit.tools/embed/en-US/fraction-calculator"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="Fraction Calculator"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
Find a common denominator (the product or the LCM of the denominators), convert the fractions and add the numerators. Example: 1/2 + 1/3 = 3/6 + 2/6 = 5/6. The tool does this automatically.
Calculations run in your browser with exact arithmetic. No data is sent to a server.